Remote-controlled circuit breaker

Abstract

A remote-controlled circuit breaker has an operation mechanism unit (300), for selecting one of an off state and a remote-controllable state of the circuit breaker, and a compact electromagnetic unit (200) and a movable contact (11, 12) which makes/breaks contact with a fixed contact in connection with a motion of the electromagnetic unit only in the remote-controllable state; and the movable contact breaks contact with the fixed contact irrespective of the motion of the electromagnetic unit at the time when an overcurrent tripping unit (400) is operated by a fault.

What is claimed is: 
     
       1. A remote-controlled circuit breaker comprising: a casing;   a fixed contact fixedly mounted to said casing;   a movable contact movably mounted to said casing to move in and out of contact with said fixed contact;   an electromagnetic unit comprising   a channel-shaped magnet frame which has a pair of opposing end-plane portions and is fixedly mounted to said casing,   a cylindrical electromagnetic coil mounted in said magnet frame,   an E-shaped fixed iron core, a central leg of which is inserted into said electromagnetic coil from one side of said electromagnetic coil and a pair of both sides legs are inserted into said magnet frame from said one side through a pair of openings of said end-plane portions, thereby to be fixed to said magnet frame,   an E-shaped movable iron core, a central leg of which is inserted into said electromagnetic coil through an opening of said magnet frame from the other side of said electromagnetic coil and a pair of both sides legs are inserted into said magnet frame from said other side through said opening of said magnet frame, thereby to be movable to said magnet frame,   a transmission lever which is pivotally mounted to said magnet frame,   a holder which is held by an end part of said transmission lever to hold said movable iron core into and out of contact with said fixed iron core, and   a spring which urges said movable iron core away from said fixed iron core;   a control lever which is pivotally mounted to said casing to move said movable contact into and out of contact with said fixed contact;   operation means, including an operation handle, for releasably holding said control lever, said operation means forming a toggle and holding said control lever in a position for moving said movable contact out of contact with said fixed contact when said operation handle is in a first position and releasing said control lever to allow a predetermined rotation thereof when said operation handle is in a second position;   an overcurrent tripping unit for causing said operation means and said control lever to actuate to move said movable contact out of contact with said fixed contact when a current greater than a predetermined value flows through said circuit breaker; and   a transmission lever which is pivotally mounted to said casing to transmit a motion of said movable iron core to said control lever.   
     
     
       2. A remote-controlled circuit breaker in accordance with claim 1, further comprising an elastic element which is provided between a projecting part of said movable iron core and each of said end-plane portions of said magnet frame to fix said fixed iron core to said magnet frame.   
     
     
       3. A remote-controlled circuit breaker in accordance with claim 1, wherein said transmission lever is disposed outside said magnet frame, and said holder holds said movable iron core at the outside of said magnet frame.   
     
     
       4. A remote-controlled circuit breaker in accordance with claim 3, further comprising an auxiliary switch which is provided outside said magnet frame to be actuated by detecting a motion of said holder.